Make forwardDims() optional and handle data dependency

See aidge_core!104 (merged).

unit_tests/Test_AvgPoolingImpl.cpp

@@ -80,7 +80,6 @@ TEST_CASE("[gpu/operator] AvgPooling(forward)", "[AvgPooling][GPU]") {
         op->associateInput(0,myInput);
         op->setDataType(DataType::Float32);
         op->setBackend("cuda");
-        op->computeOutputDims();
         myAvgPool->forward();
 
         float* computedOutput   = new float[myOutput->size()]();
@@ -113,7 +112,6 @@ TEST_CASE("[gpu/operator] AvgPooling(forward)", "[AvgPooling][GPU]") {
         op->associateInput(0,myInput2);
         op->setDataType(DataType::Float32);
         op->setBackend("cuda");
-        op->computeOutputDims();
         myAvgPool->forward();
 
         float* computedOutput   = new float[myOutput->size()]();
@@ -147,7 +145,6 @@ TEST_CASE("[gpu/operator] AvgPooling(forward)", "[AvgPooling][GPU]") {
         op->associateInput(0,myInput2);
         op->setDataType(DataType::Float16);
         op->setBackend("cuda");
-        op->computeOutputDims();
         myAvgPool->forward();
 
         half_float::half* computedOutput   = new half_float::half[myOutput->size()]();